Ensure that searx settings are preserved during upgrades

src/freedombone-app-searx

 }
 
 function upgrade_searx {
+    settings_file=${SEARX_PATH}/searx/searx/settings.yml
     background_image=/etc/searx/searx/static/themes/courgette/img/bg-body-index.jpg
     if [ -f ${background_image} ]; then
         cp ${background_image} ${background_image}.prev
     fi
+    cp ${settings_file} ${settings_file}.prev
 
     set_repo_commit $SEARX_PATH/searx "searx commit" "$SEARX_COMMIT" $SEARX_REPO
     if [ -f ${background_image}.prev ]; then
         cp ${background_image}.prev ${background_image}
         chown -R searx:searx ${SEARX_PATH}/searx
     fi
+    if [ -f ${settings_file}.prev ]; then
+        cp ${settings_file}.prev ${settings_file}
+        chown -R searx:searx ${SEARX_PATH}/searx
+    fi
 }
 
 function backup_local_searx {